1. Field of the Invention
The present invention relates to a turntable device for changing a direction of an optical apparatus such as a camera and a lamp, and relates to an optical apparatus incorporating the turntable device thereinto.
2. Description of the Related Art
It is important that an optical apparatus such as a camera and a lamp decides a direction toward an object. In the camera, for example, by determining an optimum camera angle obtained from pointing the camera at the object in various directions, a well-composed picture can be obtained. Heretofore, as camera angle adjusting means, a manual turntable has been devised, and then a remote-controlled motor-driven turntable has been developed. Recently, surveillance TV cameras are frequently placed thereon for use in an indoor or outdoor surveillance system.
For example, a motor-driven camera turntable device shown in FIGS. 35 and 36 is known. FIG. 35 is an external view of a conventional camera turntable for a surveillance camera; FIG. 36 is a perspective view of the interior of the turntable for illustrating the rotating mechanism of the camera turntable. Referring to FIG. 35, a camera turntable 303 is attached on a horizontal turntable 305, and to the camera turntable 303, a video camera 302 is fixed with camera bases 304 therebetween. The horizontal turntable 305 has functions of rotating a camera direction on a horizontal plane by a horizontally rotating mechanism, which will be described later. The camera bases 304 are installed to the camera turntable 303 with an up-and-down swinging shaft 308 therebetween, and has functions of swinging the camera on a vertical plane by an up-and-down swinging mechanism, which will be described later. The camera can be directed in an arbitrary direction at every angle.
FIG. 36 is a perspective view of the rotating mechanism of the camera turntable 303 for illustrating the internal structure thereof. A horizontally rotational shaft 306 is an axis, about which the camera turntable 303 is rotated on a horizontal plane, and the shaft 306 is fixed to the horizontal turntable 305 with a bearing mechanism (not shown) therebetween. The horizontal turntable 305 is connected to a horizontally rotation motor 311 with a gear/rack mechanism (not shown) therebetween, so that the turntable 305 is rotated about the horizontally rotational shaft 306 by the horizontally rotation motor 311.
To the horizontal turntable 305, supports 307 are attached, which support an up-and-down swinging shaft 308. The up-and-down swinging shaft 308 is connected to an up-and-down swinging motor 312 with an up-and-down swinging fixture 313, which comprises a gear/rack mechanism, therebetween. The up-and-down swinging shaft 308 is also fixed to the camera bases 304, to which a video camera is fixed. By such a structure, the video camera is moved about the up-and-down swinging shaft 308 in up-and-down directions by the up-and-down swinging motor 312.
The above-described structure swings the video camera 302 in an arbitrary direction at every angle by the combination of the horizontally rotation motor 311 with the up-and-down swinging motor 312, so that the video camera 302 can be precisely directed toward an object. Thereby, it is assumed that the camera can be directed by remote control operation using electrical signals.
In addition, referring to FIG. 35, a camera case 301 is a protection case for protecting an outdoor-use camera from natural environment.
However, the following problems have been encountered in the camera turntable device described above. The reduction in size and weight is limited because of the mechanical structure such as a motor and gear/rack mechanism, and the mechanical backlash is not avoided so as to be difficult in obtaining micro angular changes and quick responsiveness, because the gear/rack mechanism is adopted in the rotation transmission. Furthermore, if the device is installed outdoors, rattle is produced in the gear/rack mechanism for the repeated stress due to wind, thereby reducing the mechanical endurance strength and producing noise.